New polymerization catalyst

ABSTRACT

An olefin polymerization catalyst comprising the reaction product of a metallocene complex of Group IVB, VB, VIb, and VIII of the Periodic Table and an excess of alumoxane.

This is a continuation of applicaition Ser. No. 808,419 filed Dec. 12,1985 and now abandoned.

This invention relates to a new composition of matter which is useful asa catalyst for the polymerization and copolymerization of olefins andparticularly useful for the polymerization of ethylene andcopolymerization of ethylene with 1-olefins having 3 or more carbonatoms such as, for example, propylene, i-butene, 1-butene, 1-pentene,1-hexene, and 1-octene; dienes such as butadiene, 1,7-octadiene, and1,4-hexadiene or cyclic olefins such as norbornene. The inventionparticularly relates to a new transition metal containing composition ofmatter which can be employed as an olefin polymerization catalystwithout the use of an organometallic cocatalyst. The invention furthergenerally relates to the method of preparing the new composition ofmatter and to a process for polymerization of ethylene alone or withother 1-olefins or diolefins in the presence of the new transition metalcontaining catalyst comprising the reaction product of a metallocene andan alumoxane.

DESCRIPTION OF THE PRIOR ART

Traditionally, ethylene and 1-olefins have been polymerized orcopolymerized in the presence of hydrocarbon insoluble catalyst systemscomprising a transition metal compound and an aluminum alkyl Morerecently, active homogeneous catalyst systems comprising abis(cyclopentadienyl)titanium dialkyl or abis(cyclopentadienyl)zirconium dialkyl, an aluminum trialkyl and waterhave been found to be useful for the polymerization of ethylene. Suchcatalyst systems are generally referred to as "Ziegler-type catalysts".

German patent application No. 2,608,863 discloses the use of a catalystsystem for the polymerization of ethylene consisting of bis(cyclopentadienyl) titanium dialkyl, aluminum trialkyl and water.

German patent application No. 2,608,933 discloses an ethylenepolymerization catalyst system consisting of zirconium metallocenes ofthe general formula (cyclopentadienyl)_(n) ZrY_(4-n), wherein n standsfor a number in the range of 1 to 4, Y for R, CH₂ AlR₂, CH₂ CH₂ AlR₂ andCH₂ CH(AlR₂)₂, wherein R stands for alkyl or metallo alkyl, and analuminum trialkyl cocatalyst and water.

European patent application No. 0035242 discloses a process forpreparing ethylene and atactic propylene polymers in the presence of ahalogen-free Ziegler catalyst system of (1) cyclopentadienyl compound ofthe formula (cyclopentadienyl)_(n) MeY_(4-n) in which n is an integerfrom 1 to 4, Me is a transition metal, especially zirconium, and Y iseither hydrogen, a C₁ -C₅ alkyl or metallo alkyl group or a radicalhaving the following general formula CH₂ AlR₂, CH₂ CH₂ AlR₂ and CH₂CH(AlR₂)₂ in which R represents a C₁ -C₅ alkyl or metallo alkyl group,and (2) an alumoxane.

Additional teachings of homogeneous catalyst systems comprising ametallocene and alumoxane are European patent application No. No.0069951 of Kaminsky et al, U.S. Pat. No. 4,404,344 issued Sept. 13, 1983of Sinn et al., and U.S. application Nos. 697,308 filed Feb. 1, 1985,501,588 filed May 27, 1983, 728,111 filed April 29, 1985 and 501,740filed June 6, 1983, each commonly assigned to Exxon Research andEngineering Company.

An advantage of the homogeneous catalyst system comprising a metalloceneand an alumoxane is the very high activity obtained for ethylenepolymerization. Another significant advantage is, unlike olefin polymersproduced in the presence of conventional heterogeneous Zieglercatalysts, terminal unsaturation is present in polymers produced in thepresence of these homogeneous catalysts. Nevertheless, the catalystssuffer from a disadvantage, that is, the ratio of alumoxane tometallocene is high, for example in the order of 1,000 to 1 up to ashigh as 10⁶ :1. Such voluminous amounts of alumoxane would requireextensive treatment of obtained polymer product in order to remove theundesirable aluminum. A second disadvantage of the homogeneous catalystsystem, whicn is also associated with traditional heterogeneous Zieglercatalysts, is the multiple of delivery systems required for introducingthe individual catalyst components into the polymerization reactor. Athird disadvantage is the high costs of the alumoxane.

It would be highly desirable to provide a metallocene based catalystwhich is commercially useful for the polymerization of olefins whereinthe aluminum to transition metal ratio is within respectable ranges andfurther to provide a polymerization catalyst which does not require thepresence of a cocatalyst thereby reducing the number of delivery systemsfor introducing catalyst into polymerization reactor.

SUMMARY OF THE INVENTION

In accordance with the present invention, a new composition of mattercomprising a metallocene-alumoxane reaction product is provided which isuseful as a catalyst for olefin polymerization and particularly usefulfor the production of low, medium and high density polyethylenes andcopolymers of ethylene with alphaolefins having 3 to 18 or more carbonatoms and/or diolefins having up to 18 carbon atoms or more.

The new composition of matter provided in accordance with one embodimentof this invention, comprises the reaction product of at least onemetallocene and an excess of alumoxane thereby providing ametallocene-alumoxane reaction product. In accordance with anotherembodiment of this invention, a metallocene-alumoxane catalyst which canbe usefully employed is provided as the sole catalyst component in anolefin polymerization process.

The reaction product will polymerize olefins at commercially respectablerates without the presence of the objectionable excess of alumoxane asrequired in the homogenous system.

In yet another embodiment of this invention there is provided a processfor the polymerization of ethylene and other olefins, and particularlyhomopolymers of ethylene and copolymers of ethylene and higheralpha-olefins and/or diolefins and/or cyclic olefins such as norbornenein the presence of the new catalysts.

The metallocenes employed in the production of the reaction product areorganometallic compounds which are cyclopentadienyl derivatives of aGroup IVB, VB, VIB or VIII metal of the Periodic Table (66th Edition ofHandbook of Chemistry and Physics, CRC Press [1985-86] CAS version) andinclude mono, di and tricyclopentadienyls and their derivatives of thetransition metals. Particularly desirable are metallocene complexes of aGroup IVB and VB metal such as titanium, zirconium, hafnium andvanadium. The alumoxanes employed in forming the reaction product withthe metallocenes are themselves the reaction products of an aluminumtrialkyl with water.

The alumoxanes are well known in the art and comprise oligomeric linearand/or cyclic alkyl alumoxanes represented by the formula: ##STR1## foroligomeric, linear alumoxanes and ##STR2## for ligomeric, cyclicalumoxane, wherein n is 1-40, preferably 10-20, m is 3-40, preferably3-20 and R is a C₁ -C₈ alkyl group and preferably methyl. Generally, inthe preparation of alumoxanes from, for example, aluminum trimethyl andwater, a mixture of linear and cyclic compounds is obtained

The alumoxanes can be prepared in a variety of ways. Preferably, theyare prepared by contacting water with a solution of aluminum trialkyl,such as, for example, aluminum trimethyl, in a suitable organic solventsuch as benzene or an aliphatic hydrocarbon. For example, the aluminumalkyl is treated with water in the form of a moist solvent. In apreferred method, the aluminum alkyl, such as aluminum trimethyl, can bedesirably contacted with a hydrated salt such as hydrated ferroussulfate. The method comprises treating a dilute solution of aluminumtrimethyl in, for example, toluene with ferrous sulfate heptahydrate.

PREFERRED EMBODIMENTS

Briefly, the new transition metal containing composition of matter ofthe present invention is obtained by reacting an excess of alumoxanewith at least one metallocene in the presence of a suitable solvent. Thereaction product can be employed as the sole catalyst component for thepolymerization of olefins or it can be employed in combination withother catalyst systems such as, for example, titanium halide-aluminumalkyl catalyst system.

The normally hydrocarbon soluble metallocenes and alumoxanes areconverted to a relatively hydrocarbon insoluble solid reaction productby contacting said metallocenes and alumoxanes in a suitable solvent.The order of addition in contacting the metallocene and alumoxane canvary. For example, the metallocene (neat or dissolved in a suitablesolvent) can be first added to the reaction vessel followed by theaddition thereto of the alumoxane; the alumoxane and metallocene can beadded to the reaction vessel simultaneously; the alumoxane can be firstadded to the reaction vessel followed by the addition of themetallocene. In accordance with the preferred embodiment of thisinvention the metallocene dissolved in a suitable inert hydrocarbonsolvent is added to a stirred solution of the alumoxane.

The preparation of the metallocene-alumoxane reaction product, asmentioned above, is conducted in an inert solvent, preferably ahydrocarbon solvent in which the metallocene and alumoxane are soluble.Preferred solvents include mineral oils and the various hydrocarbonswhich are liquid at reaction temperatures and in which the individualingredients are soluble. Illustrative examples of useful solventsinclude the alkanes such as pentane, iso-pentane, hexane, heptane,octane, nonane, and the like; cycloalkanes such as cyclopentane,cyclohexane, and the like; and aromatics such as benzene, toluene,ethylbenzene, diethylbenzene, and the like.

The solid catalyst prepared in accordance with this invention isgenerally sparingly soluble at ambient temperatures in aromaticsolvents, insoluble in aliphatic solvents and decomposes in polarsolvents.

Preferably, the metallocene is dissolved in a hydrocarbon in which thereaction product of the alumoxane and metallocene is largely insolublesuch as pentane. The amount of solvent to be employed can vary over awide range without a deleterious effect of the reaction. In accordancewith the preferred embodiment of this invention, the amount of solventto be employed is enough to completely dissolve the metallocene andalumoxane independently prior to addition.

The metallocene and alumoxane can be added to the reaction vesselrapidly or slowly. The temperature maintained during the contact of thereactants can vary widely, such as, for example, from about -78° C. toabout 50° C. Greater or lesser temperatures can also be employed.Preferably, the alumoxanes and metallocenes are contacted at 0° C.temperature. The reaction between the alumoxane and the metallocene israpid, and hence the reaction between the alumoxane and the metalloceneis maintained for about 2 to 60 minutes. Preferably, the reaction ismaintained for about 15 minutes at subambient temperatures. The reactionof the alumoxane and the metallocene is evidenced by the color changeand formation of a precipitate or oil.

At all times, the individual ingredients as well as the recoveredcatalyst are protected from oxygen and moisture. Therefore, thereactions must be performed in an oxygen and moisture free atmosphereand recovered in an oxygen and moisture free atmosphere. Preferably,therefore, the reaction is performed in the presence of an inert dry gassuch as, for example, helium or nitrogen. The recovered solid catalystcan be maintained in a nitrogen atmosphere, preferably a subambienttemperature.

The reaction products of the metallocene and alumoxane which aregenerally solid materials when produced in aliphatic solvents and oilswhen produced in aromatic solvents can be recovered by any well-knowntechnique. For example, the solid material can be recovered from theliquid by vacuum filtration or decantation. The oils can be recovered bydecantation, and when dried, became glassy solids. The recoveredmaterial is thereafter dried under a stream of pure dry nitrogen, driedunder vacuum, or by any other convenient manner. The recovered solid isa catalytically active material.

The solid can be usefully employed in gas phase polymerization, slurrypolymerization, or in solution polymerization.

The amount of alumoxane and metallocene usefully employed in preparationof the solid catalyst component can vary over a wide range. To obtain astable solid the mole ratio of alumoxane to metallocene must be greaterthan 12:1, such as about 12:1 to about 100:1. Ratios in the range of20-40:1 are desirable, however, the greater amounts can be usefullyemployed. The solid obtained will have an aluminum to transition metalratio in the range of about 12 to 100 moles of aluminum per mole ofmetal and preferably 12 to 30 moles of aluminum per mole of metal. Thesolid so obtained has excellent catalytic activity with respect toolefin polymerization while employing significantly lower ratios ofaluminum to transition metal as compared to the homogeneous systems,whereby polymerization is carried out by adding the alumoxane andmetallocene independently to the reactor.

The present invention employs at least one metallocene compound in theformation of the solid catalyst. Metallocene, i.e. acyclopentadienylide, is a metal derivative of a cyclopentadiene. Themetallocenes usefully employed in accordance with this invention containat least one cyclopentadiene ring. The metal is selected from Group IVB,VB, VIB, and VIII metal, preferably IVB and VB metal, preferablytitanium, zirconium, hafnium, chromium, and vanadium, and especiallytitanium and zirconium. The cyclopentadienyl ring can be unsubstitutedor contain substituents such as, for example, a hydrocarbyl substituent.The metallocene can contain one, two, or three cyclopentadienyl ringshowever two rings are preferred.

The preferred metallocenes can be represented by the general formulas:

    (Cp).sub.m MR.sub.n X.sub.q                                I

wherein Cp is cyclopentadienyl ring, M is a Group IVB, VB, VIB, ortransition metal, R is a hydrocarbyl group or hydrocarboxy having from 1to 20 carbon atoms, X is a halogen, and m=1-3, n=0-3, q=0-3 and the sumof m+n+q is equal to the oxidation state of the metal. The metal is mostpreferably in its highest formal oxidation state.

    (C.sub.5 R'.sub.k).sub.g R".sub.s (C.sub.5 R'.sub.k)MQ.sub.3-gm and

    R".sub.s (C.sub.5 R'.sub.k).sub.2 MQ'                      III

wherein (C₅ R'_(k)) is a cyclopentadienyl or substitutedcyclopentadienyl, each R' is the same or different and is hydrogen or ahydrocarbyl radical such as alkyl, alkenyl, aryl, alkylaryl, orarylalkyl radical containing from 1 to 20 carbon atoms or two carbonatoms are joined together to form a C₄ -C₆ ring, R" is a C₁ -C₄ alkyleneradical, a dialkyl germanium or silicon, or a alkyl phosphine or amineradical bridging two (C₅ R'_(k)) rings, Q is a hydrocarbyl radical suchas aryl, alkyl, alkenyl, alkylaryl, or aryl alkyl radical having from1-20 carbon atoms, hydrocarboxy radical having from 1-20 carbon atoms orhalogen and can be the same or different from each other, Q' is analkylidiene radical having from 1 to about 20 carbon atoms, s is 0 or 1,g is 0, 1 or 2, s is 0 when g is 0, k is 4 when s is 1 and k is 5 when sis 0, and M is as defined above.

Exemplary hydrocarbyl radicals are methyl, ethyl, propyl, butyl, amyl,isoamyl, hexyl, isobutyl, heptyl, octyl, nonyl, decyl, cetyl,2-ethylhexyl, phenyl and the like.

Exemplary halogen atoms include chlorine, bromine, fluorine and iodineand of these halogen atoms, chlorine is preferred.

Exemplary hydrocarboxy radicals are methoxy, ethoxy, propoxy, butoxy,amyloxy and the like.

Exemplary of the alkylidiene radicals is methylidene, ethylidene andpropylidene.

Illustrative, but non-limiting examples of the metallocenes representedby formula I are dialkyl metallocenes such asbis(cyclopentadienyl)titanium dimethyl, bis(cyclopentadienyl)titaniumdiphenyl, bis(cyclopentadienyl)zirconium dimethyl,bis(cyclopentadienyl)zirconium diphenyl, bis(cyclopentadienyl)hafniumdimethyl and diphenyl, bis(cyclopentadienyl)titanium di-neopentyl,bis(cyclopentadienyl)-zirconium di-neopentyl,bis(cyclopentadienyl)titanium dibenzyl, bis-(cyclopentadienyl)zirconiumdibenzyl, bis(cyclopentadienyl)vanadium dimethyl; the mono alkylmetallocenes such as bis(cyclopentadienyl)titanium methyl chloride,bis(cyclopentadienyl)titanium ethyl chloride,bis(cyclopentadienyl)titanium phenyl chloride,bis(cyclopentadienyl)zirconium methyl chloride,bis(cyclopentadienyl)zirconium ethyl chloride,bis(cyclopentadienyl)zirconium phenyl chloride,bis(cyclopentadienyl)titanium methyl bromide,bis(cyclopentadienyl)methyl iodide, bis(cyclopentadienyl)titanium ethylbromide, bis(cyclopentadienyl)titanium ethyl iodide,bis(cyclopentadienyl)titanium phenyl bromide,bis(cyclopentadienyl)titanium phenyl iodide,bis(cyclopentadienyl)zirconium methyl bromide,bis(cyclopentadienyl)zirconium methyl iodide,bis(cyclopentadienyl)zirconium ethyl bromide,bis(cyclopentadienyl)zirconium ethyl iodide,bis(cyclopentadienyl)zirconium phenyl bromide,bis(cyclopentadienyl)zirconium phenyl iodide; the trialkyl metallocenessuch as cyclopentadienyltitanium trimethyl, cyclopentadienyl zirconiumtriphenyl, and cyclopentadienyl zirconium trineopentyl,cyclopentadienylzirconium trimethyl, cyclopentadienylhafnium triphenyl,cyclopentadienylhafnium trineopentyl, and cyclopentadienyl-hafniumtrimethyl.

Illustrative, but non-limiting examples of II and III metallocenes whichcan be usefully employed in accordance with this invention aremonocyclopentadienyls titanocenes such as, pentamethylcyclopentadienyltitanium trichloride, pentaethylcyclopentadienyl titanium trichloride;bis(pentamethylcyclopentadienyl) titanium diphenyl, the carbenerepresented by the formula bis(cyclopentadienyl)titanium═CH₂ andderivatives of this reagent such asbis(cyclopentadienyl)Ti═CH₂.Al(CH₃)₃, (Cp₂ TiCH₂)₂, Cp₂ TiCH₂CH(CH₃)CH₂, Cp₂ Ti--CHCH₂ CH₂ ; substitutedbis(cyclopentadienyl)titanium (IV) compounds such as:bis(indenyl)titanium diphenyl or dichloride,bis(methylcyclopentadienyl)titanium diphenyl or dihalides; dialkyl,trialkyl, tetra-alkyl and penta-alkyl cyclopentadienyl titaniumcompounds such as bis(1,2-dimethylcyclopentadienyl)titanium diphenyl ordichloride, bis(1,2-diethylcyclopentadienyl)titanium diphenyl ordichloride and other dihalide complexes; silicon, phosphine, amine orcarbon bridged cyclopentadiene complexes, such as dimethylsilyldicyclopentadienyl titanium diphenyl or dichloride, methylphosphine dicyclopentadienyl titanium diphenyl or dichloride,methylenedicyclopentadienyl titanium diphenyl or dichloride and otherdihalide complexes and the like.

Illustrative but non-limiting examples of the zirconocenes Formula IIand III which can be usefully employed in accordance with this inventionare, pentamethylcyclopentadienyl zirconium trichloride,pentaethylcyclopentadienyl zirconium trichloride,bis(pentamethylcyclopentadienyl)zirconium diphenyl, the alkylsubstituted cyclopentadienes, such as bis(ethylcyclopentadienyl)zirconium dimethyl,bisβ-phenylpropylcyclopentadienyl)zirconium dimethyl,bis(methylcyclopentadienyl)zirconium dimethyl,bis(n-butyl-cyclopentadienyl)zirconium dimethyl,bis(cyclohexylmethylcyclopentadienyl)zirconium dimethyl,bis(n-octyl-cyclopentadienyl)zirconium dimethyl, and haloalkyl anddihalide complexes of the above; di-alkyl, trialkyl, tetra-alkyl, andpenta-alkyl cyclopentadienes, such as bis(pentamethylcyclopentadienyl)zirconium di-methyl, bis(1,2-dimethylcyclopentadienyl)zirconium dimethyland dihalide complexes of the above; silicone, phosphorus, and carbonbridged cyclopentadiene complexes such asdimethylsilyldicyclopentadienyl zirconium dimethyl or dihalide, andmethylene dicyclopentadienyl zirconium dimethyl or dihalide, andmethylene dicyclopentadienyl zirconium dimethyl or dihalide, carbenesrepresented by the formula Cp₂ Zr═CHP(C₆ H₅)₂ CH₃, and derivatives ofthese compounds such as Cp₂ ZrCH₂ CH(CH₃)CH₂.

Bis(cyclopentadienyl)hafnium dichloride, bis(cyclopentadienyl)hafniumdimethyl, bis(cyclopentadienyl)vanadium dichloride and the like areillustrative of other metallocenes.

The polymerization may be conducted by a solution, slurry, or gas-phasetechnique, generally at a temperature in the range of about 0°-160° C.or even higher, and under atmospheric, subatmospheric, orsuperatmospheric pressure conditions; and conventional polymerizationadjuvants, such as hydrogen may be employed if desired. It is generallypreferred to use the catalyst compositions at a concentration such as toprovide about 0.00005-0.01%, most preferably about 0.005-0.001%, byweight of transition metal (100.sup.· g metal.sup.· g⁻ 1 diluent).

A slurry polymerization process can utilize sub- or superatmosphericpressures and temperatures in the range of 40°-110° C. In a slurrypolymerization, a suspension of solid, particulate polymer is formed ina liquid polymerization medium to which ethylene, alphaolefin comonomer,hydrogen and catalyst are added. The liquid employed as thepolymerization medium can be an alkane or cycloalkane, such as butane,pentane, hexane, or cyclohexane, or an aromatic hydrocarbon, such astoluene, ethylbenzene or xylene. The medium employed should be liquidunder the conditions of the polymerization and relatively inert.Preferably, hexane or toluene is employed.

In a slurry phase polymerization, the alkyl aluminum scavenger ispreferably dissolved in a suitable solvent, typically in an inerthydrocarbon solvent such as toluene, xylene, and the like in a molarconcentration of about 1×10⁻ 3M. However, greater or lesser amounts canbe used.

A gas-phase polymerization process utilizes superatmospheric pressureand temperatures in the range of about 50° -120° C. Gas-phasepolymerization can be performed in a stirred or fluidized bed ofcatalyst and product particles in a pressure vessel adapted to permitthe separation of product particles from unreacted gases. Thermostatedethylene, comonomer, hydrogen and an inert diluent gas such as nitrogencan be introduced or recirculated so as to maintain the particles at atemperature of 50°-120° C. Trimethylaluminum may be added as needed as ascavenger of water, oxygen, and other adventitious impurities. Polymerproduct can be withdrawn continuously or semicontinuing at a rate suchas to maintain a constant product inventory in the reactor. Afterpolymerization and deactivation of the catalyst, the product polymer canbe recovered by any suitable means. In commercial practice, the polymerproduct can be recovered directly from the gas phase reactor, freed ofresidual monomer with a nitrogen purge, and used without furtherdeactivation or catalyst removal. The polymer obtained can be extrudedinto water and cut into pellets or other suitable comminuted shapes.Pigments, antioxidants and other additives, as is known in the art, maybe added to the polymer.

The molecular weight of polymer product obtained in accordance with thisinvention can vary over a wide range, such as low as 500 up to 2,000,000or higher and preferably 1,000 to about 500,000.

For the production of polymer product having a narrow molecular weightdistribution, it is preferable to employ only one metallocene in formingthe solid catalyst with the alumoxane. For broad molecular weightdistribution or broad compositional distribution polymer one employs twoor more metallocenes in forming the solid catalyst.

It is highly desirable to have for many applications, such as extrusionand molding processes, polyethylenes which have a broad molecular weightdistribution of the unimodal and/or the multimodal type. Suchpolyethylenes evidence excellent processability, i.e. they can beprocessed at a faster throughput rate with lower energy requirements andat the same time such polymers would evidence reduced melt flowperturbations. Such polyethylenes can be obtained by providing acatalyst component comprising at least two different metallocenes, eachhaving different propagation and termination rate constants for ethylenepolymerizations. Such rate constants are readily determined by one ofordinary skill in the art.

The molar ratio of the metallocenes, such as, for example, of azirconocene to a titanocene in such catalysts, can vary over a widerange, and in accordance with this invention, the only limitation on themolar ratios is the breadth of the Mw distribution or the degree ofbimodality desired in the product polymer. Desirably, the metallocene tometallocene molar ratio will be about 1:1 to about 100:1, and preferably1:1 to about 10:1.

The present invention also provides a process for producing(co)polyolefin reactor blends comprising polyethylene andcopolyethylene-alpha-olefins. The reactor blends are obtained directlyduring a single polymerization process, i.e., the blends of thisinvention are obtained in a single reactor by simultaneouslypolymerizing ethylene and copolymerizing ethylene with an alpha-olefinthereby eliminating exoensive blending operations. The process ofproducing reactor blends in accordance with this invention can beemployed in conjunction with other prior art blending techniques, forexample, the reactor blends produced in a first reactor can be subjectedto further blending in a second stage by use of the series reactors.

In order to produce reactor blends the catalyst comprises at least twodifferent metallocenes each having different comonomer reactivityratios.

The comonomer reactivity ratios of the metallocenes in general areobtained by well known methods, such as for example, as described in"Linear Method for Determining Monomer Reactivity Ratios inCopolymerization", M. Fineman and S. D. Ross, J. Polymer Science 5, 259(1950) or "Copolymerization", F. R. Mayo and C. Walling, Chem. Rev. 46,191 (1950) incorporated herein in its entirety by reference. Forexample, to determine reactivity ratios the most widely usedcopolymerization model is based on the following equations: ##STR3##where M₁ refers to a monomer molecule which is arbitrarily designated i(where i=1, 2) and M_(i) * refers to a growing polymer chain to whichmonomer i has most recently attached.

The kij values are the rate constants for the indicated reactions. Inthis case, k₁₁ represents the rate at which an ethylene unit insertsinto a growing polymer chain in which the previously inserted monomerunit was also ethylene. The reactivity rates follow as: r₁ ═k₁₁ /k₁₂ andr₂ ═k₂₂ /k₂₁ wherein k₁₁, k₁₂, k₂₂ and k₂₁ are the rate constants forethylene (1) or comonomer (2) addition to a catalyst site where the lastpolymerized monomer is ethylene (k_(lX)) or comonomer (2) (k_(2X)).

Since, in accordance with this invention, one can produce high viscositypolymer product at a relatively high temperature, temperature does notconstitute a limiting parameter as with the prior artmetallocene/alumoxane catalyst. The catalyst systems described herein,therefore, are suitable for the polymerization of olefins in solution,slurry or gas phase polymerizations and over a wide range oftemperatures and pressures. For example, such temperatures may be in therange of about -60° C. to about 280° C. and especially in the range ofabout 0° C. to about 160° C. The pressures employed in the process ofthe present invention are those well known, for example, in the range ofabout 1 to 500 atmospheres, however, higher pressures can be employed.

The polymers produced by the process of this present invention arecapable of being fabricated into a wide variety of articles, as is knownfor homopolymers of ethylene and copolymers of ethylene and higheralpha-oefins. The present invention is illustrated by the followingexamples.

EXAMPLES

In the Examples following the elemental analysis was obtained throughinductively coupled plasma emission spectroscopy on a Jarrell AshSpectrometer Model 750 manufactured by Jarrell Ash.

Bis(pentamethylcyclopentadienyl)zirconium bis-triflate was manufacturedby dissolving 2 grams of bis(pentamethylcyclopentadienyl)zirconiumdimethyl in 100 ml of toluene and cooling to -30° C. To the cooledsolution was added 1.53 grams of triflic acid (CF₃ SO₃ H). The reactionwas stirred for one hour and the solid was isolated by filtration. Thecrude product was recrystallized from dichloromethane and diethyl etheryielding 2.8 grams of yellow prisms characterized by NMR spectroscopy(Varian XL200) to bebis-pentamethylcyclopentadienyl-zirconium-bis-triflate. 1.0 grams of therecovered complex was suspended in 50 ml of toluene under constantstirring to which was added 0.11 g of trimethylaluminum. The solidreaction product began immediately to dissolve. Reaction was continuedfor 30 minutes, upon which the solvent was removed in vacuo. Therecovered product was recrystallized from toluene-pentane to yield 0.80grams of yellow crystals characterized by proton and carbon NMRspectroscopy (Varian XL200) to bebis-pentamethylcyclopentadienyl-zirconium-methyl-triflate.

The alumoxane employed was prepared by adding 76.5 grams ferrous sulfateheptahydrate in 4 equally spaced increments over a 2 hour period to arapidly stirred 2 liter round-bottom flask containing 1 liter of a 13.1wt. % solution of trimethylaluminum (TMA) in toluene. The flask wasmaintained at 50° C. and under a nitrogen atmosphere. Methane producedwas continuously vented. Upon completion of the addition of ferroussulfate heptahydrate the flask was continuously stirred and maintainedat a temperature of 50° C. for 6 hours . The reaction mixture was cooledto room temperature and was allowed to settle. The clear solutioncontaining the alumoxane was separated by decantation from the insolublesolids.

In cases where the metallocene of interest is readily soluble in asaturated hydrocarbon such as pentane, it is desirable to have themethylalumoxane dissolved in that same solvent. Pentane solutions ofalumoxane are prepared by concentrating a toluene solution of alumoxane(prepared as above) in vacuo to a clear viscous oil (i.e., where most ofthe toluene has been removed but prior to the point where a solid glassis formed). This oil is extracted with pentane to remove all pentanesoluble aluminum components. The pentane solubles are separated fromhigh molecular weight insoluble alumoxane oligomers by filtration. andanalyzed for aluminum concentration by ICPES.

EXAMPLE 1 Catalyst Preparation

To a 0.5 liter reaction flask containing 1 gram ofbis(pentamethylcyclopentadienyl)zirconium dichloride dissolved in 75 mlof toluene, there was added with constant stirring and at roomtemperature, 198 ml of a pentane solution 0.35 M in methylalumoxane. Areaction occurred immediately as evidenced by the formation of aninsoluble yellow-oil. The reaction flask was cooled to -30° C. and heldat that temperature for one hour. The oil was separated from the motherliquor by decantation, washed with 30 ml of pentane and dried in vacuoyielding 1.47 grams of a glassy solid (Solid I). The aluminum:zirconiumratio was 33:1.

Polymerization

Solid I (0.05 g) was dissolved in 100 ml of toluene, injected into a 250ml pressure reaction vessel and heated to 80° C. The vessel waspressured to 35 psi with ethylene and maintained for 20 minutes at 80°C. with constant stirring. 4.4 grams of high-density polyethylene wasisolated.

EXAMPLE 2 Catalyst Preparation

To a 0.25 liter reaction flask containing 0.75 grams ofbis(pentamethylcyclopentadienyl)zirconium dimethyl dissolved in 50 ml oftoluene, there was added with constant stirring and at room temperature,164 ml of a pentane solution 0.35 M in methylalumoxane. A reactionoccurred immediately, yielding a yellow oil. The reaction flask wascooled to -30° C. and held at that temperature for one hour. The oil wasseparated from the mother liquor, washed with 50 ml of pentane, anddried in vacuo, yielding 1.3 grams of a glassy solid (Solid II). Thealuminum:zirconium ratio was 32:1.

Polymerization

Solid II (0.05 g) was dissolved in 100 ml toluene, injected into a 250ml pressure reaction vessel and heated to 80° C. The vessel waspressured to 35 psi with ethylene and maintained for 20 minutes at 80°C. with constant stirring. 5.4 grams of high density polyethylene wasrecovered.

EXAMPLE 3 Catalyst Preparation

To a 0.25 liter reaction flask containing 1 gram ofbis(nbutylcyclopentadienyl)zirconium dichloride dissolved in 75 ml of a20:80 mixture of toluene and pentane, there was added with constantstirring, and at room temperature, 176 ml of methylalumoxane (0.35M).The reaction vessel was cooled to -30° C. and held at the temperaturefor one hour. The oil was separated from the mother liquor bydecantation, washed with 20 ml of pentane, and dried in vacuo yielding1.87 grams of a glassy solid (Solid III). The aluminum:zirconium ratiowas 20:1.

Polymerization

Solid III (0.05 g) was dissolved in 100 ml toluene, injected into a 250ml reaction vessel and heated to 80° C. The vessel was pressured to 35psi with ethylene and maintained for 10 minutes at 80° C. with constantstirring. 8.2 grams of high density polyethylene was isolated.

EXAMPLE 4 Catalyst Preparation

To a 0.25 liter reaction flask containing 0.50 grams ofbis(cyclopentadienyl)titanium methyl chloride dissolved in 75 ml oftoluene, there was added with constant stirring and at room temperature,156 ml of a pentane solution 0.35 M in methylalumoxane. A chemicalreaction occurred as evidenced by the immediate formation of a deep redoil. The reaction vessel was cooled to -30° C. and held at thattemperature for a one hour period. The oil was separated from the motherliquor by decantation, washed with 50 ml pentane, and dried in vacuo,yielding 2.78 grams of a glassy solid (Solid IV). The aluminum:titaniumratio was 20:1.

Polymerization

Solid IV (0.05 g) was dissolved in 100 ml toluene, injected into a 250ml pressure reaction vessel and heated to 80° C. The vessel waspressured to 35 psi with ethylene and maintained for 20 minutes at 80°C. with constant stirring. 3.8 grams of high density polyethylene wasisolated.

EXAMPLE 5 Catalyst Preparation

To a 0.25 liter reaction flask containing 0.71 grams ofbis(pentamethylcyclopentadienyl)zirconium-methyl-triflate dissolved in100 ml of toluene, there was added, with constant stirring and at roomtemperature, 97 ml of a pentane solution 0.35 M of methylalumoxane. Areaction occurred immediately as evidenced by the formation of aninsoluble yellow oil. The reaction vessel was cooled to -30° C. and heldat that temperature for one hour. The oil was separated from the motherliquor by decantation, washed in 50 ml of pentane and dried in vacuo,yielding 1.80 grams of a glassy solid (Solid V). The aluminum:zirconiumratio was 68:1.

Polymerization

Solid V (0.05 g) was dissolved in 100 ml of toluene, injected into a 250ml pressure reaction vessel and heated to 80° C. The vessel waspressured to 35 psi with ethylene was maintained for 20 minutes at 80°C. and with constant stirring. 3.2 grams of polyethylene was isolated.

EXAMPLE 6 Catalyst Preparation

To a 0.25 liter reaction flask containing 1 gram ofbis(pentamethylcyclopentadienyl)titanium dichloride dissolved in 60 mlof toluene there was added, with constant stirring and at roomtemperature, 80 ml of a pentane solution 0.79 M in methylalumoxane. Areaction occurred immediately as evidenced by the formation of asparingly soluble deep red oil. The reaction vessel was cooled to -30°C. and held at that temperature for one hour. The oil was separated fromthe mother liquor, washed in 50 ml of pentane and dried in vacuo,yielding 1.95 grams of a glassy solid (Solid VI). The aluminum:titaniumratio was 17:1.

Polymerization

Solid VI (0.05 g) was dissolved in 100 ml of toluene, injected into a250 ml pressure reaction vessel and heated to 80° C. The vessel waspressured to 35 psi with ethylene and maintained for 20 minutes at 80°C. with constant stirring. 0.9 gram of polyethylene was isolated.

EXAMPLE 7 Catalyst Preparation

To a 0.25 liter reaction flask containing 0.75 grams ofbis(nbutylcyclopentadienyl)titanium dichloride dissolved in 100 ml of an80:20 mixture of pentane and toluene there was added, with constantstirring and at room temperature, 66 ml of a pentane solution 0.35 M inmethylalumoxane. A reaction occurred immediately as evidenced by theformation of an insoluble red oil. The reaction vessel was cooled to-30° C. and held at that temperature for one hour. The oil was separatedfrom the mother liquor, washed in 50 ml of pentane and dried in vacuo,yielding 0.75 grams of a glassy solid (Solid VII). The aluminum:titaniumratio was 24:1.

Polymerization

Solid VII (0.05 g) was dissolved in 100 ml of toluene, injected into a250 ml pressure reaction vessel and heated to 80° C. The vessel waspressured to 35 psi with ethylene and maintained for 20 minutes at 80°C. with stirring. 3.2 grams of high density polyethylene was isolated.

EXAMPLE 8 Catalyst Preparation

To a 0.25 liter reaction flask containing 1 gram ofbis(cyclopentadienyl)titanium diphenyl dissolved in 100 ml of an 80:20mixture of pentane and toluene there was added, with constant stirringand at room temperature, 95 ml of a pentane solution 0.79 M inmethylalumoxane. A reaction occurred immediately forming an insolubleoil. The reaction vessel was cooled to -30° C. and held at thattemperature for one hour. The oil was separated from the mother liquor,washed in 50 ml of pentane and dried in vacuo, yielding 0.70 grams of aglassy solid (Solid VIII). The aluminum:titanium ratio was 17:1.

Polymerization

Solid VIII (0.05 g) was dissolved in 100 ml of toluene, injected into a250 ml pressure reaction vessel and heated to 80° C. The vessel waspressured to 35 psi with ethylene and maintained for 20 minutes at 80°C. with constant stirring. 2.9 grams of high density polyethylene wasisolated.

EXAMPLE 9 Catalyst Preparation

To a 0.25 liter reaction flask containing 0.5 grams ofbis(cyclopentadienyl)zirconium dimethyl dissolved in 100 ml of a 90:10mixture of pentane and toluene there was added, with constant stirringand at room temperature, 63 ml of a pentane solution 0.79 M inmethylalumoxane. A reaction occurred immediately as evidenced by theformation of an off-white precipitate. The reaction vessel was cooled to-30° C. and held at that temperature for one hour. The precipitate wascollected by filtration, washed with 50 ml of pentane and dried invacuo, yielding 1.9 grams of a white solid (Solid IX). Thealuminum:zirconium ratio was 21.7:1.

Polymerization

Solid IX (0.05 g) was dissolved in 100 ml of toluene, injected into a250 ml pressure reaction vessel and heated to 80° C. The vessel waspressured to 35 psi with ethylene and maintained for 10 minutes at 80°C. with constant stirring. 7.2 grams of high density polyethylene wasisolated.

What is claimed is:
 1. An olefin polymerization catalyst comprising thesolid reaction product obtained by reacting at least one metallocene ofa metal of Group IVB of the Periodic Table with an alumoxane at a ratioof 1:12 to about 1:100 on a molar basis based on the metal and aluminum.2. The olefin polymerizatin catalyst in accordance with claim 1 whereinthe metallocene is selected from titanium, zirconium, and hafniummetallocenes and mixtures thereof.
 3. The olefin polymerization catalystin accordance with claim 2 wherein the metallocene is selected fromtitanium and zirconium metallocenes and mixtures thereof.
 4. The olefinpolymerization catalyst in accordance with claim 1 wherein the alumoxaneis methyl alumoxane.
 5. The olefin polymerization catalyst in accordancewith claim 1 wherein the ratio is in the range of 12:1 to 30:1.
 6. Theolefin polymerization catalyst in accordance with claim 1 wherein themetallocenes are represented by the formulas

    (Cp).sub.m MR.sub.n X.sub.q                                (I)

    (C.sub.5 R'.sub.k).sub.g R".sub.s (C.sub.5 R'.sub.k)MQ.sub.3-g (II)

and

    R".sub.s (C.sub.5 R'.sub.k).sub.2 MQ'

wherein Cp is a cyclopentadienyl ring, M is a Group IVB, VB, VIB or VIIItransition metal, R is a hydrocarbyl group or hydrocarboxy having from 1to 20 carbon atoms, X is a halogen, m=1-3, n=0-3, q=0-3 and the sum ofm+n+q is equal to the oxidation state of M, (C₅ R'_(k))is acyclopentadienyl or a substituted cyclopentadienyl; each R' is the sameor different and is hydrogen or a hydrocarbyl radical selected fromalkyl, alkenyl aryl, alkylaryl or arylalkyl radicals containing from 1to 20 carbon atoms, two carbon atoms are joined togther to form a C₄ -C₆ring, R" is a C₁ -C₄ alkylene radical, a dialkyl germanium or silicon oran alkyl phosphine or amine radical bridging two (C₅ R'_(k)) rings; Q isa hydrocarbyl radical selected from aryl, alkyl, alkenyl, alkylaryl, orarylalkyl radicals having from 1-20 carbon atoms, hydrocarboxy radicalhaving from 1-20 carbon atoms or halogen and can be the same ordifferent from each other; Q' is an alkylidiene radical having from 1 toabout 20 carbon atoms; s is 0 or 1; g is 0, 1, or 2; s is 0 when g is 0;k is 4 when s is 1 and k is 5 when s is
 0. 7. The olefin polymerizationcatalyst in accordance with claim 6 wherein the metallocenes areselected from bis(cyclopentadienyl) zirconium dichloride,bis(cyclopentadienyl)zirconium methyl chloride, bis(cyclopentadienyl)zirconium dimethyl, bis(methylcyclopentadienyl)zirconium dichloride,bis(methylcyclopentadienyl)zirconium methyl chloride,bis(methylcyclopentadienyl)zirconium dimethyl,bis(pentamethylcyclopentadienyl)zirconium dichloride,bis(pentamethylcyclopentadienyl)zirconium methyl chloride,bis(pentamethylcyclopentadienyl)zirconium dimethyl,bis(n-butyl-cyclopentadienyl) zirconium dichloride,bis(n-butylcyclopentadienyl)zirconium methyl chloride,bis(n-butyl-cyclopentadienyl)zirconium dimethyl,bis(cyclopentadienyl)titanium diphenyl, bis(cyclopentadienyl)titaniumdichloride, bis(cyclopentadienyl)titanium methyl chloride,bis(cyclopentadienyl)titanium dimethyl,bis(methylcyclopentadienyl)titanium diphenyl,bis(methylcyclopentadienyl) titanium dichloride,bis(methylcyclopentadienyl)titanium diphenyl,bis(methylcyclopentadienyl)titanium methyl chloride,bis(methylcyclopentadienyl)titanium dimethyl,bis(pentamethylcyclopentadienyl)titanium dichloride,bis(pentamethylcyclopentadienyl)titanium diphenyl,bis(pentamethylcyclopentadienyl)titanium methyl chloride,bis(pentamethylcyclopentadienyl)titanium dimethyl,bis(n-butyl-cyclopentadienyl)titanium diphenyl,bis(n-butyl-cyclopentadienyl)titanium dichloride and mixtures thereof.8. A method for preparing an olefin polymerization catalyst comprisingreacting at least one metallocene of a metal of Group IVB of thePeriodic Table in a solvent in an amount sufficient to completelydissolve the metallocene with an alumoxane in a solvent in an amountsufficient to completely dissolve the alumoxane at a ratio of 1:12 toabout 1:100 on a molar basis on the metal and aluminum.
 9. An alumoxane,metallocene reaction product wherein the ratio of aluminum to metal isin the range of 12:1 to 100:1 and the metal is a Group IVB metal.